﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Input;
using System.Diagnostics;

namespace Lepton_Practical_MVVM_6_1.Framework {
    public class RelayCommand : ICommand {

        #region Fields

        readonly Action<object> _execute;
        readonly Predicate<object> _canExecute;

        #endregion // Fields

        #region Constructors

        public RelayCommand(Action<object> execute)
            : this(execute, null) {
        }
        public RelayCommand(Action<object> execute, Predicate<object> canExecute) {
            if (execute == null)
                throw new ArgumentNullException("execute");
            _execute = execute;
            _canExecute = canExecute;
        }

        #endregion // Constructors

        #region ICommand Members

        [DebuggerStepThrough]
        public bool CanExecute(object parameter) {
            return _canExecute == null ? true : _canExecute(parameter);
        }

        public event EventHandler CanExecuteChanged {
            add {
                CommandManager.RequerySuggested += value;
            }
            remove {
                CommandManager.RequerySuggested -= value;
            }
        }

        public void Execute(object parameter) {
            _execute(parameter);
        }

        #endregion // ICommand Members
    }
}
